Imaging of Circulatory Disturbances Flashcards
What are anatomical vascular imaging methods?
- Plain films
- Contrast angiography
- Ultrasound
- CT/MRI
What are functional vascular imaging methods?
- Radionuclide imaging
- MRI functional imaging
- Ultrasound
What are problems with vascular imaging?
- Soft tissue contrast
- Functional significance of lesions
- Is treatment effective
What is the problem with using contrasts?
We can’t see some important structures very well:
- Blood vessels
- Lumen of hollow viscera
What are the ideal properties of a man-made contrast agent in radiology?
- Inert: won’t react with body of tissues
- Painless
- Easy to use
Features of Iodinated contrasts?
- Differential Xray attentuation
- Inert
- Stable in selected body compartments
- Painless
- Easy to use
- Cheap
What are problems with Iodinated contrasts?
- Major reactions
- Renal dysfunction
- Disurbance of thyroid metabolism
- Disturbance of clotting
- Seizures
- Pulmonary oedema
Features of Parental Iodinated contrast
- Metallic taste
- Feeling of warmth
- Arterial injections: Micturition, discomfort
- Rarely nausea
Metformin and contrast agents
Metformin is a drug used to treat type II diabetes
- This can cross react with contrast agents!
Features of catheter angiography
- Vessel punctures and catherised
- Sterile procedure
- Contrast injected using pump injector
- Rapid series of images acquired
Interventional Radiology: minimal invasive treatment techniques
- Angiography/Angioplasty
- Embolisation
- Catheter thrombolysis
- Drainage of abscesses
- Nephrostomy
- Vertebroplasty
When would you use Angioplasty?
- Short stenoses or occlusions
- Sessile/concentric plaques
- Iliac > sfa > popliteal > crural
- “not as long lasting as surgery but not as dangerous”
What else is used apart from Iodine containing contrast agents?
Carbon Dioxide
- A negative contrast agent!
- Useful in patients with poor renal function or sensitivity to iodinated contrast agents.
- CO2 gets absorbed really quickly in vessels.
What are problems with Angioplasty?
- Occlusion
- Dissection
- Embolisation
- Rupture
- Infection
Features of Ultrasound
- No radiation dose
- Quick
- Non-invasive
- Resolution vs Penetration
- May be physiological
- Operator dependant
A man presents with a swollen leg. An ultrasound test confirms a Deep Venous Thrombosis.
What does the ultrasound show?
The vein is distended and non-compressible on gentle pressure of the ultrasound probe
Features of normal vein on ultrasound
Normal vein has low pressure and is compressible
DVT - vein is full of thrombus and is not compressible
What can Radionuclide imaging be used for?
- Perfusion
- Blood loss
- Perfusion of transplant kidneys
- Blood loss into gastrointestinal tract
Features of V/Q (ventilation perfusion scan)
It is useful in the evaluation of pulmonary embolism
Features of Nuclear Medicine
- IV injection only
- Good patient compliance
- Radiation dose
- Very insensitive
- Very non-specific
- Easy to arrange
Features of Computed Tomography Angiogram
- Gives information about other structures
- Sensitive
- IV injection only
- Radiation dose
- High contrast dose
- Expensive
Features of Magnetic Resonance Angiography
- Sensitive
- Specific
- no radiation
- No nephrotoxic contrast
- Very expensive
- Needs state of the art machinery
- High contrast cost
